Two followers of a fundamentalist Christian church that favours faith healing over conventional medicine are to be prosecuted for manslaughter after their daughter died of a treatable infection.

Carl and Raylene Worthington were indicted by a grand jury in Oregon's Clackamas county following the death of their 15-month-old daughter Ava in March.

The toddler died of bronchial pneumonia and a blood infection, according to the state medical examiner's office - both conditions that could have been treated with antibiotics.

The parents, who surrendered to police on Friday, are members of the Followers of Christ, a fundamentalist church in Oregon with about 1,500 members. They were released on $250,000 (£126,000) bail.

The church was at the centre of controversy in the 1990s after the deaths of several children attracted the attention of the authorities. It led to the passage of legislation in Oregon that repealed the right to a religious beliefs defence in cases of manslaughter, homicide and child abuse.

Since the passage of the law in 1999, according to authorities in Oregon, there have been no incidents of child neglect involving the church. The Worthingtons are the first members of the church to face criminal charges for failing to seek medical attention for a gravely ill child. If convicted they could serve six years in prison for manslaughter and up to a year for criminal mistreatment.

The couple's son died in August 2001. A police investigation into the death was closed after family members said the child had been stillborn and was three months premature.

Despite the passage of the law and the tight-knit nature of the congregation, there are some indications of high infant mortality among the group. The church has a private cemetery south of Oregon City. There, markers indicate that more than half a dozen children have died of unspecified causes since the passage of the legislation nine years ago.

The Followers of Christ has its origins in the Pentecostal movement of the late 19th century.